Can I synchronize a TMS device Trigger with a Powerlab?

In neurophysiology research, the precise timing between a stimulus and a physiological response is critical. Synchronizing a Transcranial Magnetic Stimulation (TMS) device with PowerLab is essential to establish an accurate temporal relationship between the TMS pulse and the recorded signal (e.g., an EMG response). This synchronization is essential for calculating latencies, defining analysis windows, etc.

The synchronization of Powerlab with two common TMS systems: Magstim and MagVenture are detailed. If you need help with integrating other TMS devices, please contact ADInstruments Technical Support.

Hardware Setup

The connections and appropriate cables are essential to send a trigger-out signal from the TMS device to the PowerLab's trigger input, creating a precise time-marker for each stimulus.

Please Note: The methods described below apply to PowerLab models that feature a dedicated "Trigger" input. It is not applicable to the PowerLab C, which does not have this specific trigger port.

Connecting a Magstim Device (200² / BiStim²)

  1. Attach the DB26 connector of the Magstim Interface Cable (MLAC60, Supplied by ADInstruments) to the "Isolated interface" port on the rear of the Magstim.
  2. Connect the red BNC cable (TRIGGER OUT) from the cable to the dedicated "Trigger" input on the PowerLab.

Connecting a MagVenture Device (MagPro Series)

  1. Attach the DB9 connector of the Cable for External Triggering with BNC (9016E456- supplied by MagVenture) to the "Trig in/Trig out" port on the rear of the MagVenture unit.

  2. Connect the BNC cable labeled Trig Out from the cable to the dedicated "Trigger" input on the PowerLab.

  3. On the MagVenture control unit, navigate the menu to Trigger Menu -> Trigger output and ensure it is set to Enabled. And, change the Polarity, Output -> Rising Edge. The device will not send a trigger signal otherwise.

LabChart Setup (Common for Both Systems) 

Once the hardware is correctly wired, the setup within the LabChart software is identical for both systems. The incoming trigger from the TMS device acts as a precise event marker that LabChart can use in several ways.

  • Triggering a Recording: You can configure your LabChart recording to begin automatically upon receiving a signal from the external trigger input. This is useful for creating discrete trials centered around the stimulus. To configure this, click Setup -> Sampling -> Change Source to "External Trigger"

 

  •  Adding Comments or Markers: In a continuous recording, the trigger signal can be used to automatically drop a marker or a preset comment (e.g., "TMS Pulse") into the data file. This is the most common method, as it allows for easy navigation and analysis of the data post-recording. To configure this, click Setup -> Preset Comments -> New -> Choose "External Trigger" in Event Configuration -> Edit Comment text 

For further technical assistance with this or any other issue, please contact ADInstruments Technical Support by clicking HERE.